Skip to main content
U.S. flag

An official website of the United States government

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.


Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Experimental Evidence for s-Wave Pairing Symmetry in Superconducting Cu_{x}Bi_{2}Se_{3} Single Crystals Using a Scanning Tunneling Microscope



Niv Levy, Tong Zhang, Jeonghoon Ha, Fred Sharifi, Alec Talin, Young Kuk, Joseph A. Stroscio


Topological superconductors (TS) are a newly predicted phase of matter which is topologically distinct from conventional superconducting condensates of Cooper pairs. As a manifestation of its topological character, TS supports massless itinerant quasi-particles on the boundary, which are solid-state realizations of Majorana fermions. The recently discovered superconductor CuxBi2Se3 has been theoretically proposed as an odd-parity superconductor in the time-reversal-invariant TS class. Here we report scanning tunneling spectroscopy (STS) measurements of the superconducting energy gap in CuxBi2Se3 as a function of spatial position and applied magnetic field. The tunneling spectrum shows that the density of states at the Fermi level is fully gapped without any in-gap states. The spectrum is well described by the Bardeen-Cooper-Schrieffer (BCS) theory with a momentum independent order parameter, which strongly suggests that Cu0.2Bi2Se3 is a classical s-wave superconductor contrary to previous expectations.
Physical Review Letters


Topological superconductors, scanning tunneling microscopy, scanning tunneling spectroscopy
Created March 12, 2013, Updated February 19, 2017